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Frequent Sea, Cored decks and the fungus farm
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Captains Cat



Joined: 03 Nov 2003
Posts: 7313
City/Region: Cod Creek>Potomac River>Chesapeake Bay
State or Province: VA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Captain's Choice II
Photos: Captain's Cat
PostPosted: Tue May 22, 2007 3:17 pm    Post subject: Reply with quote

Bob, what's an "unsealed core"? Just no protection where fittings are mounted, or what?

Charlie

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CHARLIE and PENNY CBRAT #100
Captain's Cat II 2005 22 Cruiser
Thataway (2006 TC255 - Sold Aug 2013)
Captain's Cat (2006 TC255 - Sold January 2012)
Captain's Kitten (1995 CD 16 Angler- Sold June 2010)
Captain's Choice (1994 CD 22 Cruiser- Sold Jun 2007)
Potomac River/Chesapeake Bay
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue May 22, 2007 5:25 pm    Post subject: Reply with quote

Charlie, that is correct: any core material which is not sealed with epoxy. At times poyester is used--and is used on the transom of the C Dory 25 on the top and polyester with a layer of mat is used to seal the 3/4" pieces of plywood (2) which make up the 1 1/2" wooden core of the transom. Fiberglass with resin is often not stiff enough in a flat pannel, nor does it have the strength, so core is added to make it stronger, stiffer, or to fill a void (like engine stringers).

Epoxy has much better adhesive properties than polyester. Many of the early Taiwan boats were made with cabin sides and decks of layers of fiberglass over plywood--(vs the plywood molded into the glass). Many of these trawlers have gotten rot in the plywood core, because it was not sealed.

Another typical case is in production boat where the hull and engine stringers are wood encapsulated in polyester resin and glass cloth. Then limber holes (drain holes) are cut, but the wood is not sealed. Moisture gets into the wood (core) and then rot forms.

Balsa is semi sealed--it is actually a "hardwood" by definition. That is the cells are short, even though the wood its self is soft. As you may remember the Kon Tiki got lower and lower in the water, as the balsa logs adsorbed water. The end grain balsa theoretically should not absorb
water if each cell is sealed. Unfortuanately the polyester does not adhere well enough to the balsa, and water is adsorbed. I will be adding a piece on balsa in the transom thread as soon as I post the photos, and some new findings today--related to un-sealed core.

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Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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Captains Cat



Joined: 03 Nov 2003
Posts: 7313
City/Region: Cod Creek>Potomac River>Chesapeake Bay
State or Province: VA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Captain's Choice II
Photos: Captain's Cat
PostPosted: Tue May 22, 2007 7:49 pm    Post subject: Reply with quote

Thanks Bob. What type of the Nida-Core did you use? There are several kinds on their website. I've got a cabin top on a Columbia 26 sailboat to repair, where the mast step fitting leaked in the way of the bolts. It made the top so spongy that the guy that had it was afraid of it. It's not bad now that it's dried out but I'm going to cut the top skin off, pull out the core and replace it. There are two bulkheads under it and 4 vertical posts that'll give me lots of support. Was going to use Balsa but the Nida-Core looks better.

Charlie
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue May 22, 2007 8:19 pm    Post subject: Reply with quote

Under a mast step I would use solid marine plywood, epoxy saturated--you can use core material around the sides if you need--but under a direct compression post--there can be too much point compression for the Nida-core, or most foams. You would have to spread out the load some way, even with a high glass content, and a heel plate. I have seen a lot of deck fitted masts which broke down core material, including plywood (especially when it got wet) (there are some exotics which are light and will work--but not worth it for this application).

We used the 8HPP Nida-core.
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Adeline



Joined: 03 Nov 2003
Posts: 985
City/Region: Vancouver
State or Province: WA
C-Dory Year: 1989
C-Dory Model: 22 Cruiser
Vessel Name: Adeline
Photos: Adeline
PostPosted: Tue May 22, 2007 9:33 pm    Post subject: Reply with quote

Hi Charlie, When you get around to re-installing your mast step THIS may be helpful.
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Captains Cat



Joined: 03 Nov 2003
Posts: 7313
City/Region: Cod Creek>Potomac River>Chesapeake Bay
State or Province: VA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Captain's Choice II
Photos: Captain's Cat
PostPosted: Wed May 23, 2007 8:36 am    Post subject: Reply with quote

Thanks Pete, that looks nifty, I'll take a hard look at it. I like the idea of not having the bolts go all the way through the cabin top. Not quite sure how thick it is there yet, haven't cut into it. I have a 30x38 metal building to put together before I start this project! Shocked

Bob, the step isn't directly over the supports but rather in the middle of about a 2.5' X 2.5' square that has the support posts (really a part of the bulkheads of the cabin underneath) at the corners. I will probably put plywood in there though, that sounds like a smart idea!

Thanks for the info on the Nida-Core.

Charlie
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Wed May 23, 2007 9:12 pm    Post subject: Reply with quote

My recollection of the Columbia 26 is that there was a laminated beam between the two bulkheads--and the area above this was plywood core.
There were 2 x 2" pieces of mahagony grooved on one side for the bulkhead, and the beam was over this. (I am thinking of the Mark I--S & S designed. If you are thinking of the Mark II, Bill Trip designed, it was relitatively similar--but I think a more substantial lamination.
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stclairgal



Joined: 14 Feb 2013
Posts: 55
City/Region: St Clair Shores
State or Province: MI
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: Dragonfly
Photos: Dragonfly
PostPosted: Sat Dec 02, 2017 12:42 pm    Post subject: Rotted Core around deck plate Reply with quote

Hi everyone,
thought I would re-activate this topic and warn everyone to check their cockpit deck plates. I knew ours were leaking when we opened the gas tank access port and found a pretty deep layer of scum. It caused our fuel level sensor to stop working. With the help of a generous fellow C-Brat we got the wires cleaned up and reconnected - problem solved! (Thanks again Tom!!)
I removed the deck plate this morning to reseal things and found the wood core all around the plate to be mush, in some spots almost two inches in. I am digging out the rotten core and will let things dry out over the winter. In the spring we will follow Bob Austin's great instructions for replacing the core and sealing the opening with epoxy.
If anyone has any additional tips let me know!
I'll post a couple of pics of my mess in the Dragonfly album.
This is a great forum. Proud to be a C-brat!

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Joyce and Wolfgang
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sat Dec 02, 2017 6:34 pm    Post subject: Reply with quote

Thanks for the kind words, and reminders! I am going to check out that 2006 boat in Pensacola--and see if that is an issue there!

I had commented that I had assurances from the factory in 2007 that there would no longer be any leaks--that the 2007 boat would not have that problem....well--they do--and I suspect even newer ones also will. A lot depends on how the boat has been stored, and if there have been leaks, water intrusion and freeze thaw cycles.

Hopefully your core issues will only be a few inches, and you will not have to do the total rebuild. But it may be a good time to check out the fuel tank--and prevent any issues there also.

Regards,
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South of Heaven



Joined: 15 Aug 2015
Posts: 1459
City/Region: Sharon
State or Province: MA
Photos: Blue Water
PostPosted: Sat Dec 02, 2017 8:32 pm    Post subject: Reply with quote

Its so weird to see all the posters from this thread. Most of them are not active anymore. Sad
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<><><> Jason <><><>

2005 Silverton 35 Motoryacht (Twin 385 Crusaders) (SOLD 6/20)

2000 Camano 31 Troll (Volvo TAMD41p) (SOLD 2/19)

2007 C Dory 25' Cruiser (200 hp Suzuki, sold 7/17)

2003 C Dory 19' Angler (80 hp Yamaha, sold 7/16)

1995 C Dory 16' Angler (40 hp Yamaha, sold 2/16)
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sat Dec 02, 2017 8:40 pm    Post subject: Reply with quote

South of Heaven wrote:
Its so weird to see all the posters from this thread. Most of them are not active anymore. :(

Really? I am still quite active. I hear from Capt Charlie periodically, Brent B is certainly active. I hear from most of the others every now and then...maybe not frequent posters, but certainly around.
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South of Heaven



Joined: 15 Aug 2015
Posts: 1459
City/Region: Sharon
State or Province: MA
Photos: Blue Water
PostPosted: Sat Dec 02, 2017 9:09 pm    Post subject: Reply with quote

thataway wrote:
South of Heaven wrote:
Its so weird to see all the posters from this thread. Most of them are not active anymore. Sad

Really? I am still quite active. I hear from Capt Charlie periodically, Brent B is certainly active. I hear from most of the others every now and then...maybe not frequent posters, but certainly around.


Yes, Brent and you are very active. It's just interesting for new Brats like myself to see these "foreign" names on the old threads! Lol. A different time I guess. Most online forums are very cyclical in nature.
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T.R. Bauer



Joined: 17 Nov 2007
Posts: 1726
City/Region: Wasilla
State or Province: AK
C-Dory Year: 1993
C-Dory Model: 22 Cruiser
Vessel Name: C-Whisperer
PostPosted: Sun Dec 03, 2017 12:40 pm    Post subject: Reply with quote

That's it! I'm posting just to post Smile
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South of Heaven



Joined: 15 Aug 2015
Posts: 1459
City/Region: Sharon
State or Province: MA
Photos: Blue Water
PostPosted: Sun Dec 03, 2017 1:53 pm    Post subject: Reply with quote

T.R. Bauer wrote:
That's it! I'm posting just to post Smile


Good!
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Jack in Alaska



Joined: 17 Aug 2004
Posts: 1190
City/Region: Anchorage/Ninilchik
State or Province: AK
C-Dory Year: 2005
C-Dory Model: 26 Pro Angler
Vessel Name: HIGH TIDE II
Photos: HIGH TIDE II
PostPosted: Mon Dec 04, 2017 1:33 pm    Post subject: old timers Reply with quote

What T. R. Bauer said.............. C-Dory owner since 1983

Jack (still in Alaska)

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On the HIGH TIDE-II, wife Carolyn and I.....Another summer fishing on the HIGH TIDE II in the Cook Inlet at Cape Ninilchik, Alaska.

HIGH TIDE-II; 2005 26' ProAngler; 2003 200 Honda / 2009 9.9 Honda high thrust
No. CD026021I405; AK-5008-AK
MSSI No. 338143486(cancelled)

HIGH TIDE; 1983 Angler Classic 22'; 90 Honda/ 9.9 Tohatsu-sold 2009 to son Dan (flatfishfool)
Stolen & stripped in Aug. 18
Bare hull & trailer sold in Nov.
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